Self-Initializing CRT Adapter for Multiple CRT Types
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
This article describes a programmable CRT adapter which determines the type of monitor which is attached to it and generates appropriate signals for driving the monitor. The CRT adapter shown above includes a CRT controller (CRTC) which is a very large-scale integration (VLSI) vendor module. The module can be purchased off the shelf and generates timing signals necessary to drive logic that drives the CRT (not shown). The fundamental signals (for example, vertical sync, horizontal sync and video) that drive the CRT are all determined by the frequency outputted from the programmable (PROG) clock and the programming of the CRTC. The read/write (RW) control circuit driving this clock is a programmable divide-down circuit that gives up to six different base frequencies.